HVAC systems comprise various interworking components: furnaces, heat exchanger, pipes, ducts and more. Often an HVAC system will comprise at least two control boards. One controller will be a central controller, with a processor directing the activity of the entire system. A furnace will usually have its own separate controller and processor. The central controller and the furnace controller will often be networked together, either by a line or wireless. The central controller will often have a connection to a monitoring or central station. This can be via the local internet connection, cellular or another method.
As it has become easier to monitor HVAC systems from a remote location it has also become desirable to add or change functionality in an installed system. Users would like to turn on/off a system remotely (such as via a mobile application) and manufacturers would like to be able to monitor the systems. All of this functionality requires software and capable processors on the central and furnace controllers. Because software is used there will sometimes be a need to update that software or other functionality of the controllers. However, some elements of HVAC systems, especially furnace functionalities, must pass onerous safety certifications, such as CSA (Canadian Standards Association) or OSHA (Occupational Safety & Health Administration) certifications. A controller that goes through a software update may lose certification.